Optical dimensioning systems measure the dimensions and/or volume of an item (e.g., a package for shipment) automatically and with no manual measurements. One approach to optical dimensioning requires the projection of an optical pattern (i.e., structured light) onto the object being measured. Digital images of the object and the reflected pattern may be captured and analyzed to determine the item's physical dimensions.
An optical pattern projector creates and projects the optical pattern necessary for dimensioning. The optical pattern typically includes repeating patterns (i.e., sub-patterns) of light spots (i.e., dots). A variety of methods to form the repeating optical pattern exists.
One method uses a single laser and two diffractive optical elements (i.e., DOE's). Here, the laser generates a laser beam that is directed at the first DOE to create a sub-pattern. Next, light from the first DOE is directed at a second DOE, which replicates the sub-pattern to form the repeating optical pattern.
Another method to create the optical pattern uses a custom laser array to form the sub-pattern of light. Light from the custom laser array is directed at a DOE to replicate the sub-pattern and form the optical pattern.
The methods thus far described have similar drawbacks. The use of two DOE's and the use of a custom laser array increase the cost and complexity of the optical pattern projector. A need, therefore, exists for a simpler optical pattern projector for structured-light dimensioning.